Many lighting devices have the function of reflecting ones beam output to the particular direction the user desires. Many prior art devices (e.g. stage lighting devices) move the light source and reflective/refractive optics together. A common approach involves the use of a pan motor to rotate the entire tilt assembly. The drawback of this approach is bulkiness and it requires a large pan motor. Complicated slip ring design has to be added in order to achieve continuous multiple pan rotations because otherwise the wire supplying power to the tilt motor will limit the pan rotation angle. As high power LED has overtaken fluorescent lights in terms of efficacy (i.e. light flux output per unit electrical power input), it is natural to use LED light source instead of incandescent (very low efficacy) or compact fluorescent light source (contains mercury). Since size of LEDs is much smaller as compared to fluorescent lights giving same amount of light output, it is now possible to implement light reflecting function within a small space such as a light bulb. However, conventional approaches are not feasible because of the unique characteristics of high power LEDs. One characteristic of high power LED is that the heat generated during usage must be conducted away in order to keep the junction temperature below its operating limit (e.g. 125 degree Celsius), or otherwise permanent degradation or even total destruction will happen. The most common approach is by adding heatsink function to the outer casing of the LED lighting device (such as a light bulb) and keeping the thermal resistance between the LED and the heatsink as low as possible. Unlike prior arts that use other types of light sources, now there is a need for a new light reflecting mechanism such that reflecting the light output from the LED (can be an array of LEDs) does not require moving the LED at all. The reason is that it is difficult to move the LED while keeping a good heat dissipation path without moving the heatsink which is heavy in weight. Moving the bulky heatsink is often not acceptable. For example, the lamp base of a light bulb which fits into a lamp socket is the only mechanical mounting available for a light bulb. The connection between a lamp base and a lamp socket is rigid along the longitudinal direction but weak along the horizontal direction. Moving heavy mass inside the light bulb will result in swinging like a pendulum, resulting in the illuminated spot moving to and fro which is unacceptable by user.
The above description of the background is provided to aid in understanding a heat dissipating light reflecting device, but is not admitted to describe or constitute pertinent prior art to the heat dissipating light reflecting device disclosed in the present patent application, or consider any cited documents as material to the patentability of the claims of the present patent application.